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Legionnaires' disease
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Legionnaires' disease is an atypical pneumonia, meaning a lung infection that does not behave like classic pneumonia, and it is potentially severe and often fatal. It is part of legionellosis, whose two main syndromes are this disease and Pontiac fever.
It is caused by a gram-negative bacillus, a rod-shaped bacterium that does not retain the Gram stain and that lives in water. It reaches the lungs when a person inhales or aspirates aerosols of contaminated water, tiny suspended droplets.
Once inside the alveolus, the little sac where the lung exchanges gases, it does something striking. It enters the alveolar macrophages, the very cells whose job is to engulf and kill bacteria in the lung, and it blocks that killing ability. The bacterium gets inside the lung's guard and uses it as a home: that macrophage becomes the place where the bacterium multiplies.
In brief
Legionnaires' disease is an atypical pneumonia, potentially severe and often fatal; it and Pontiac fever are the two main syndromes of legionellosis.
It is caused by a gram-negative bacillus that lives in aquatic environments and reaches the lungs when contaminated water aerosols are inhaled or aspirated.
Once in the alveolus, it enters alveolar macrophages, blocks their bactericidal activity and turns them into sites of replication.
The bacterium gets inside the lung's guard and uses it as a home.
Sources (1)
- National Center for Biotechnology Information, StatPearls PublishingLegionnaires' Disease, StatPearlsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
Updated